Display screen or portion thereof with transitional graphical user interface



FIG. 1 is a front view of the first image in a sequence for a display screen or portion thereof with transitional graphical user interface, showing our new design;

FIG. 2 is a front view of the second image thereof;

FIG. 3 is a front view of the third image thereof;

FIG. 4 is a front view of the fourth image thereof;

FIG. 5 is a front view of the fifth image thereof;

FIG. 6 is a front view of the sixth image thereof;

FIG. 7 is a front view of the seventh image thereof;

FIG. 8 is a front view of the eighth image thereof;

FIG. 9 is a front view of the ninth image thereof;

FIG. 10 is a front view of the tenth image thereof; and,

FIG. 11 is a front view of the eleventh image thereof.

The outer perimeters illustrated by a pair of broken lines represent display screens or portions thereof and forms no part of the claimed design.

The appearance of the transitional graphical user interface sequentially transitions between the images shown in FIGS. 1-11. The process or period in which one image transitions to another forms no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with transitional graphical user interface, as shown and described. 